The war on drugs is driving much of the global AIDS pandemic, increasing new infections among injection-drug users in the U.S. and elsewhere, according to a new report from the Global Commission on Drug Policy.

The commission — led by a distinguished panel including the former presidents of Mexico, Poland, Colombia, Brazil and Switzerland, along with Virgin Airlines entrepreneur Richard Branson, the former chair of the Federal Reserve, Paul Volcker, and former Secretary of State George Schulz, among others — finds in its report that about one-third of all new infections outside of sub-Sarahan Africa occur in injection-drug users.

Since the 1990s, effective public-health strategies to curb HIV transmission in drug users have led to drops in new infections in most countries. But over the same time period, seven countries have seen a 25% increase in new infections. Not coincidentally, five of these countries — mainly in Eastern Europe and Central Asia — employ aggressive drug war strategies, such as arresting and incarcerating users for drug or needle possession.

These tactics have been shown to be ineffective not only for controlling drug use, but also for reining in the spread of HIV. Why? Because the fear of recrimination prevents drug users from seeking clean needles — a major risk factor for HIV infection. In the U.S. as well, areas with the highest infection rates are those that have the most aggressive drug policies, the report shows. The solution is straightforward, if drastic; it requires a complete overhaul of current drug policy: drug users need treatment, not imprisonment, and drug possession needs to be decriminalized, the authors argue.

Look no further than New York City, the epicenter of the American HIV epidemic among drug users in the late 1980s and early ’90s, as testament to the effects of a policy about-face. Twenty-five years ago, city law enforcement was battling outdoor drug markets by arresting users en masse; at the same time, the city reported a 50% HIV infection rate among people who injected drugs.

In the early ’90s, the situation began to change. The city started expanding methadone prescribing to help treat users addicted to drugs. Needle-exchange programs, run illegally mostly by AIDS activists from ACT UP, began to be established. At the start, the activists deliberately provoked arrest — but soon the courts would rule that the public health benefits of the programs outweighed any merits of keeping them illegal. Over time, many of the underground needle-exchange programs grew into legal, government-funded operations.

The rate of HIV infection among IV drug users in New York City has fallen by two-thirds since its peak; while injection-drug use once accounted for half of all new infections in the city, today it is linked to fewer than 5%.

The strategy has worked in other cities as well: a 1997 study f0und that HIV infection rates in U.S. cities without needle-exchange programs increased 6% per year; in contrast, infection rates in cities that had clean-needle programs fell by the same amount. International data presented in the new report tell the same story: when access to needles and methadone treatment is expanded — and when drug users do not have to fear arrest for possession of needles — HIV infection rates fall.

Research also shows that the reverse is true. A study published in The Lancet in2010 found that nearly one-fifth of all HIV infections in the Ukraine may be associated with police beatings of IV drug users during arrest. Because possession of needles can be grounds for arrest and attack, fear of police keeps drug users from obtaining clean needles.

The countries hardest hit by drug-war driven HIV include Russia and many other regions of the former Soviet Union. Russia’s situation is especially dire because it bans methadone maintenance treatment for those addicted to opioids like heroin. This, despite the fact that the World Health Organization and other expert bodies that have examined the question scientifically have determined that maintenance is more effective than other treatments at reducing drug-related crime, death and the spread of blood-borne disease.

Russia’s opposition is ideological: maintenance is viewed as the simple substitution of one harmful drug for another; the data show, however, that maintenance dramatically improves health. Currently, 37% of all IV-drug users in Russia are HIV-positive. Globally, infection among IV-drug users tends to drive heterosexual and pediatric infections in epidemics outside of Africa.

The U.S. isn’t immune to the problem either: a longstanding federal ban on funding for needle exchange, which was briefly lifted in 2011, was reinstated this year. The effects of Congress’s AIDS policies have been felt most profoundly at its doorstep in Washington, D.C., which has the highest rate of HIV infection in the country. Because of D.C.’s unique status, Congress can also prevent the city from using its own funds for needle exchange, which it was barred from doing until 2008. (That year, D.C.’s local ban was lifted, though the federal ban remains.) The result: at roughly 3%, our nation’s capital has a higher HIV infection rate than Ethiopia or Sierra Leone.

In America, the war on drugs disproportionately harms black communities. African American men are at least twice as likely to be arrested or imprisoned for drug crimes as white men. Further, jails and prisons house people at high risk of HIV infection together — about 25% of people with HIV pass through correctional facilities annually — while limiting or denying access to condoms, let alone clean needles. Even a short jail term doubles the risk of syringe sharing and increases the risk of HIV-medication failure by a factor of seven, according to a Baltimore study cited in the Global Commission’s report. It’s not surprising, then, that while African Americans make up 12% of the U.S. population, they account for 50% of new HIV infections.

The commission’s AIDS report concludes: “Any sober assessment of the impacts of the war on drugs would conclude that many national and international organizations tasked with reducing the drug problem have actually contributed to a worsening of community health and safety. This must change.”

The authors call for complete decriminalization of drug possession by users who are harming no one but themselves, as well as greater access to maintenance treatment, needle exchange and other services. Politically, however, we might be more likely to see Republicans increase taxes for the rich and Democrats eliminate Social Security and Medicare.

But it doesn’t have to be that difficult; the data here clearly point to specific solutions. Researchers know what works to fight HIV, and they also know that it is far cheaper to prevent infection than it is to treat it. More than ever before, the evidence also reveals how best to combat addiction — arresting users for needle or drug possession does not help.